Self adhering membrane for roofing applications

ABSTRACT

A preformed, self adhering single ply roofing membrane including a water impermeable membrane; a pressure sensitive, hot melt adhesive adhered to one side of the water impermeable membrane, and a release liner on the side of the pressure sensitive, hot melt adhesive opposite of the water impermeable membrane.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/461,327, filed 31 Jul. 2006 and presently pending, which is adivisional of U.S. application Ser. No. 10/153,132, filed 22 May 2002and issued as U.S. Pat. No. 7,101,598 on 5 Sep. 2006, the entiredisclosures of each being incorporated herein by reference.

BACKGROUND INFORMATION

1. Field of the Invention

The present invention relates generally to a self adhering membrane forroofing applications. More particularly, the present invention relatesto a preformed self adhering single ply roofing membrane including apressure sensitive, hot melt adhesive adhered to one side of a waterimpermeable membrane.

2. Description of Related Art

A roofing system generally includes a roof deck which is considered thestructural supporting surface of a building extending between thesurrounding exterior walls of the building. The roof deck may beconstructed from plywood, metal decking or concrete or any othersuitable material. Depending upon the construction, the roof deck mayextend over the surrounding exterior walls or the roof deck may stopshort of the exterior walls thereby forming a parapet wall, i.e., a lowretaining wall at the edge of the roof deck. If desired, the roofingsystem may also include an insulation barrier formed frompolyisocyanurate or any other suitable material applied over the roofdeck.

To make the roof deck and building weather resistant a single-plyroofing membrane is installed over the roof deck. The single-ply roofingmembrane refers to a water impermeable single sheet of polymericmaterial. The roofing membrane has heretofore been installed on the roofdeck using a variety of different methods.

For example, the field or interior of the roofing membrane may be heldto the roof deck by the use of ballast and/or penetrating ornon-penetrating fastener means as known in the art. An example of apenetrating fastener means for retaining the field of a roofing membraneinstalled to a roof deck is by utilizing a plurality of small, circular,metal plates having a hole in the center and a roofing screw or othersuitable fastener. In order to anchor the roofing membrane, the small,circular, metal plates are spaced apart in rows on the roofing membraneand the fastener is driven through the hole in each plate, the roofingmembrane, any insulation material and then into the roof deck. The metalplates are then covered by an overlapping roof membrane. An example of anon-penetrating fastener means would include totally adhering the fieldof the roofing membrane to the roof deck.

Although the many known variations for attaching a roofing membrane to aroof deck have been proven to perform satisfactorily under certainconditions, further improvements on attaching a roofing membrane to aroof deck are desired.

The present invention is directed to a self adhering membrane forroofing applications. More particularly, the present invention relatesto a preformed self adhering single ply roofing membrane including apressure sensitive, hot melt adhesive adhered to one side of a waterimpermeable membrane for application to a roofing deck and/or a parapetwall to form a water impermeable roofing membrane.

SUMMARY OF THE INVENTION

Briefly, the present invention relates to a preformed single ply roofingmembrane including a water impermeable membrane; a pressure sensitive,hot melt adhesive adhered to one side of the water impermeable membrane,wherein the pressure sensitive adhesive is free of a curing additive;and a release liner on the side of the pressure sensitive, hot meltadhesive opposite of the water impermeable membrane.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the present invention, as well as the advantagesderived therefrom, will become clear from the following detaileddescription made with reference to the drawings in which:

FIG. 1 is a cross sectional view of a preformed roofing membrane inaccordance with one aspect of the present invention;

FIG. 2 is a cross sectional view of a preformed roofing membrane inaccordance with another aspect of the present invention; and

FIG. 3 is a preformed roofing membrane in accordance with another aspectof the present invention.

DETAILED DESCRIPTION

Referring the figures, wherein like reference characters represent likeelements, there is shown a preformed self adhering roofing membrane 10in accordance with the present invention. As noted, the preformed selfadhering roofing membrane 10 includes a substrate sheet of waterimpermeable membrane 12, a pressure sensitive, hot melt adhesive 14adhered to one side of the water impermeable membrane, and a releaseliner 16 on the side of the pressure sensitive, hot melt adhesiveopposite of the water impermeable membrane.

The preformed self adhering roofing membrane 10 is securely attached toa roof substrate comprising a roof deck or parapet wall or curb to forma water impervious structure. The roof deck and/or parapet wall and/orcurb may be constructed from plywood, metal decking or concrete or anyother suitable material. On existing construction, the self adheringroofing membrane 10 may be applied to a smooth asphalt top surface. Ifdesired, the roofing system may also include an insulation barrierformed from polyisocyanurate or any other suit-able material appliedover the roof deck. A suitable primer may be used on the roof substratesurface to enhance the adhesion of the self adhering roof membrane.

The water impermeable membrane 12 of the preformed self adhering roofingmembrane 10 is formed of, for example, appropriate thermosettingmaterials and thermoplastic materials including polyvinyl chloride(PVC), thermoplastic olefin (TPO), polyethylene and polypropylene,chlorinated polyethylene (CPE), chloro-sulphinated polyethylene (CSPE)and polyisobutylene (PIB). Suitable thermosetting materials are EPDM,butyl rubber, and neoprene. These preformed self adhering single plyroofing membranes 10 may or may not include reinforcing meshes or scrimslocated intermediate layers 12 and 14 of the material forming the singleply roofing membrane. The water impermeable membrane 12 may range fromabout 0.020-0.090 inches thick, preferably 0.045-0.090 inches thick.

The water impermeable membrane 12 may range from about 6 inches-12 feetwide and of indeterminate length depending upon the intendedapplication. For example, when the preformed self adhering membrane 10is installed over the parapet wall or curb of a roofing installation thewater impermeable membrane ranges from 6 inches-3 feet in width andindeterminate in length as desired.

Adhered to one side of the water impermeable membrane 12 is the pressuresensitive, hot melt adhesive 14. The pressure sensitive, hot meltadhesive 14 is applied directly to the water impermeable membrane 12using most any suitable method well known in the art. For example, thepressure sensitive, hot melt adhesive 14 may be applied directly to thewater impermeable membrane 12 using a hot melt spray method or by usinga slot die method as well known in the art. It will be appreciated thatby applying the pressure sensitive, hot melt adhesive 14 directly to thewater impermeable membrane 12 better and more uniform bond strength maybe achieved in contrast to the use of a transfer adhesive.

Pressure sensitive, hot melt adhesives 14 in accordance with the presentinvention are solvent-free adhesives, that are characteristically solidat temperatures below 180° F., are low viscosity fluids above 180° F.,and rapidly set upon cooling. Exemplary of pressure sensitive hot meltadhesives are ethylene vinyl acetate (EVA) copolymers, compatible withparaffin; styrene-isoprene-styrene (SIS) copolymers;styrene-butadiene-styrene (SBS) copolymers; ethylene ethyl acrylatecopolymers (EEA); and polyurethane reactive (PUR), butyl or halo-butylrubbers, acrylic, ethylene propylene rubber (EPR), ethylene propylenediene terpolymer rubber (EPDM) or styrene/butadiene rubbers (SBR) andstyrene-ethylene-butene-styrene copolymers (SEBS) including a variety oftackifying resins, and optionally waxes, antioxidants, plasticizers, andother materials added to the adhesive formulation to enhance the polymerperformance. In order to be considered useful for the preformed singlyply roofing membrane 10 in accordance with the present invention, thepressure sensitive, hot melt adhesive 14 should not include a curing orcross linking agent whereby the adhesive maintains the desiredthermo-plastic properties. The pressure sensitive hot melt adhesive 14must have a minimum peel strength of 0.5 pounds per linear inch at 70°F. as determined in accordance with ASTM D 3330 for roofingapplications.

By way of a representative example only, a particular preferred pressuresensitive, hot melt adhesive 14 is PSA-3 Hot Melt Adhesive commerciallyavailable from ADCO Products, Inc.

The pressure sensitive, hot melt adhesive 14 thickness may range fromabout 0.004 inches to 0.015 inches.

A release liner 16 is applied against the pressure sensitive, hot meltadhesive 14 surface to prevent premature unwanted adhesion and, in thecase of rolls, ease of unwind with-out sticking to the backing. Releaseliner 16 is applied after the application of the pressure sensitive hotmelt adhesive 14. For ease of application, the release liner 16 may besliced into multiple sections to allow for portioned release of theliner from the water impermeable membrane during application of thepreformed self adhering membrane 10. Release liner 16 may comprisepaper, or polyethylene, polypropylene or polyester films of a type wellknown in the art.

As shown in FIG. 1, the water impermeable membrane 12; pressuresensitive, hot melt adhesive 14 and release liner 16 may beco-extensive. During application, two self adhering membranes 10 may bejoined by positioning the membranes in overlapping relation and thenheat welding or adhesively bonding the overlapping edges or if themembranes are butted together, a cover cap may be adhered or hot airwelded over the seam. In alternate embodiment, as shown in FIG. 2, therelease liner 16 and pressure sensitive hot melt adhesive 14 may becoextensive and the combined release liner 16 and pressure sensitiveadhesive 14 may be spaced from at least one marginal edge of the waterimpermeable membrane 12 to provide a free edge of water impermeablemembrane. The free edge of water impermeable membrane 12 may overlap anadjacent water impermeable membrane and be either hot air welded orsolvent based adhered or tape adhered to the overlapped membranedepending upon the type of water impermeable membrane to be joined. Inyet another embodiment as shown in FIG. 3, the pressure sensitive, hotmelt adhesive 14 and the release liner 16 may be coextensive and thecombined release liner and pressure sensitive adhesive may be spacedfrom at least one marginal edge of the water impermeable membrane. Thefree edge of water impermeable membrane includes a cured, pressuresensitive adhesive composition 18 including a release liner as describedin U.S. Pat. No. 5,242,727, incorporated herein by reference. Thepreformed self adhering membranes 10 may be joined together byoverlapping the cured pressure sensitive adhesive 18 and the waterimpermeable membrane 12 and then removing a release liner 20 andpressing adhesive 18 of one membrane against the other membrane.

The preformed self adhering membrane 10 as shown in the figures isjoined to the roof substrate by removing the release liner 16 and thenpressing the pressure sensitive, hot melt adhesive 14 directly to theroof substrate.

The patents and documents described herein are hereby incorporated byreference.

Having described presently preferred embodiments of the invention, theinvention may be otherwise embodied within the scope of the appendedclaims.

While the invention has been specifically described in connection withcertain specific embodiments thereof, it is to be understood that thisis by way of illustration and not of limitation, and the scope of theappended claims should be construed as broadly as the prior art willpermit.

1. A membrane product capable of adhering to a roof deck, said membraneproduct having two primary exterior surfaces, said membrane productcomprising: a) a single-ply roofing membrane; and b) a layer of pressuresensitive adhesive that is free of curing additives, said adhesive layerhaving a thickness of no more than 15 mils, said adhesive layer directlycontacting at least a portion of one side of said single-ply roofingmembrane, and said single-ply roofing membrane constituting one of saidtwo primary exterior surfaces of said membrane product.
 2. The membraneproduct of claim 1 wherein said pressure sensitive adhesive is a hotmelt.
 3. The membrane product of claim 2 wherein said pressure sensitiveadhesive includes a copolymer selected from styrene-isoprene-styrene,styrene-butadiene-styrene, ethylene-propylene, andstyrene-ethylene-butene-styrene.
 4. The membrane product of claim 3wherein said pressure sensitive adhesive further comprises plasticizer.5. The membrane product of claim 2 wherein said pressure sensitiveadhesive includes butyl or halo-butyl rubber.
 6. The membrane product ofclaim 5 wherein said pressure sensitive adhesive further comprisesplasticizer.
 7. The membrane product of claim 2 wherein said pressuresensitive adhesive is solvent-free.
 8. The membrane product of claim 1wherein said single-ply roofing membrane has a thickness of from 45 to90 mils.
 9. The membrane product of claim 1 wherein said single-plyroofing membrane is a TPO membrane.
 10. The membrane product of claim 1wherein said single-ply roofing membrane is an EPDM membrane.
 11. Themembrane product of claim 1 wherein said pressure sensitive adhesivelayer constitutes the other of said two primary exterior surfaces ofsaid membrane product.
 12. The membrane product of claim 1 furthercomprising a release liner disposed on said pressure sensitive adhesivelayer, said release liner constituting the other of said two primaryexterior surfaces of said membrane product, said product optionallybeing provided in roll form with said product being wound around thelength of a roller core.
 13. A membrane product capable of adhering to aroof deck, said membrane product having two primary exterior surfaces,said membrane product comprising: a) a single-ply roofing membranehaving a thickness of from 45 to 90 mils; and b) a layer of hot-meltpressure sensitive adhesive that is free of curing additives, saidadhesive layer having a thickness of no more than 15 mils, said adhesivelayer directly contacting at least a portion of one side of saidsingle-ply roofing membrane, and said single-ply roofing membraneconstituting one of said two primary exterior surfaces of said membraneproduct.
 14. The membrane product of claim 13 wherein said pressuresensitive adhesive includes a copolymer selected fromstyrene-isoprene-styrene, styrene-butadiene-styrene, ethylene-propylene,and styrene-ethylene-butene-styrene.
 15. The membrane product of claim14 wherein said pressure sensitive adhesive further comprisesplasticizer.
 16. The membrane product of claim 13 wherein said pressuresensitive adhesive includes butyl or halo-butyl rubber.
 17. The membraneproduct of claim 16 wherein said pressure sensitive adhesive furthercomprises plasticizer.
 18. The membrane product of claim 13 wherein saidsingle-ply roofing membrane is a TPO membrane.
 19. The membrane productof claim 13 wherein said single-ply roofing membrane is an EPDMmembrane.
 20. The membrane product of claim 13 further comprising arelease liner disposed on said pressure sensitive adhesive layer, saidrelease liner constituting the other of said two primary exteriorsurfaces of said membrane product, said product optionally beingprovided in roll form with said product being wound around the length ofa roller core.